1. Field of the Invention
The current invention relates to the field of adapters and more particularly to the field of edge launch adapters.
2. Description of Related Art
For high-frequency applications, establishing a connection between a signal line on a substrate, such as a printed circuit board (PCB), and a cable such as a coaxial cable can be expensive and problematic.
In some cases, edge launch adapters, also known as edge adapters or edge launchers, may be attached to the edge of a PCB and transition the signal to a coaxial cable. This type of configuration is popular for use with high frequency applications. A typical edge launch configuration may use a launcher, also called a coaxial cable connector, for coupling to a coaxial cable, a PCB and a bracket to provide support for coupling the launcher to the PCB. In many cases, a small central pin embedded in a glass bead may be housed in the bracket and used to establish the connection between the signal line on the PCB and the center conductor of the launcher. Typically, a designer will select a central pin diameter corresponding to the desired operating frequency; small diameter central pins may be used for high frequency applications whereas larger diameter central pins may be used for lower frequency applications. Typically, the cost of the glass bead as well as the cost of the launcher relates to the diameter size of the central pin. Usually, small diameter central pins require the use of high precision, expensive launchers such as Anritsu's K-type or V-type cable connectors (2.92 mm and 1.85 mm connectors, respectively) instead of less expensive launchers such as SubMiniature Version A (SMA) type cable connectors. Furthermore, depending on the board design, insertion losses and return losses can become problematic. Insertion losses and return losses are especially problematic for multi-layer PCBs with multiple metal layers. Long ground paths coupled to vias near the edge of the PCB can introduce unwanted input and output return loss and jitter.
Accordingly, it is desirable to have an inexpensive and robust method for establishing a connection between a planar signal line on a substrate and a cable capable of supporting operation over a wide frequency range. Ideally, the solution should work with any type of planar circuit module using any type of substrate, such as ceramic and organic substrates, and any type of PCB, such as a single or multi-layer PCB and provide a smooth transition from the planar circuit to the coaxial cable with low insertion losses and low return losses. Preferably, the solution may be implemented using currently available technologies and incorporated into currently available processes.